The invention relates to a method for measuring impulse periods and fault locations in cables and light wave conductors, having a generator for voltage impulses or light impulses which are then fed into the measured object and having a directional coupler which conducts the impulses reflected back from the test specimen to a detector.
Such methods are primarily performed with reflectometers, whereby an oscilloscope display is generally necessary to evaluate the measurement. Particularly for fault location in light wave conductors in accordance with the backscattering process, expensive electronic equipment is necessary in order to be able to recognize the desired signals on the display screen. Sample-and-hold circuits or similar integration methods are usually used in this situation.
An optical time-range reflectometer is known for determining the attenuation of light conducting fibers, which consists of a light source, a beam divider, a detector, an amplifier, a signal processor and a display device as well as associated control units. In this known reflectometer the signal processor consists of a sample and hold circuit, by means of which the backscatter signal released periodically by an impulse carrier is scanned (DE-OS 28 37 981).
The backscatter signals displayed on the screen of this type of reflectometer can be evaluated in four ways and permit conclusions to be drawn with regard to a series of characteristics of the measured light wave conductor. In many instances, particularly in seeking faults, a small portion of the presented information is sufficient.